// Copyright (c) 2015-2016 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.

#ifndef BITCOIN_MEMUSAGE_H
#define BITCOIN_MEMUSAGE_H

#include <indirectmap.h>
#include <prevector.h>
#include <support/allocators/pool.h>

#include <cassert>
#include <cstdlib>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <unordered_map>
#include <unordered_set>
#include <vector>

namespace memusage {

/** Compute the total memory used by allocating alloc bytes. */
static size_t MallocUsage(size_t alloc);

/** Dynamic memory usage for built-in types is zero. */
static inline size_t DynamicUsage(const int8_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const uint8_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const int16_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const uint16_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const int32_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const uint32_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const int64_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const uint64_t &v) {
    return 0;
}
static inline size_t DynamicUsage(const float &v) {
    return 0;
}
static inline size_t DynamicUsage(const double &v) {
    return 0;
}
template <typename X> static inline size_t DynamicUsage(X *const &v) {
    return 0;
}
template <typename X> static inline size_t DynamicUsage(const X *const &v) {
    return 0;
}

/**
 * Compute the memory used for dynamically allocated but owned data structures.
 * For generic data types, this is *not* recursive.
 * DynamicUsage(vector<vector<int>>) will compute the memory used for the
 * vector<int>'s, but not for the ints inside. This is for efficiency reasons,
 * as these functions are intended to be fast. If application data structures
 * require more accurate inner accounting, they should iterate themselves, or
 * use more efficient caching + updating on modification.
 */
static inline size_t MallocUsage(size_t alloc) {
    // Measured on libc6 2.19 on Linux.
    if (alloc == 0) {
        return 0;
    } else if (sizeof(void *) == 8) {
        return ((alloc + 31) >> 4) << 4;
    } else if (sizeof(void *) == 4) {
        return ((alloc + 15) >> 3) << 3;
    } else {
        assert(0);
    }
}

// STL data structures

template <typename X> struct stl_tree_node {
private:
    int color;
    void *parent;
    void *left;
    void *right;
    X x;
};

struct stl_shared_counter {
    /**
     * Various platforms use different sized counters here.
     * Conservatively assume that they won't be larger than size_t.
     */
    void *class_type;
    size_t use_count;
    size_t weak_count;
};

template <typename X>
static inline size_t DynamicUsage(const std::vector<X> &v) {
    return MallocUsage(v.capacity() * sizeof(X));
}

template <unsigned int N, typename X, typename S, typename D>
static inline size_t DynamicUsage(const prevector<N, X, S, D> &v) {
    return MallocUsage(v.allocated_memory());
}

template <typename X, typename Y>
static inline size_t DynamicUsage(const std::set<X, Y> &s) {
    return MallocUsage(sizeof(stl_tree_node<X>)) * s.size();
}

template <typename X, typename Y>
static inline size_t IncrementalDynamicUsage(const std::set<X, Y> &s) {
    return MallocUsage(sizeof(stl_tree_node<X>));
}

template <typename X, typename Y, typename Z>
static inline size_t DynamicUsage(const std::map<X, Y, Z> &m) {
    return MallocUsage(sizeof(stl_tree_node<std::pair<const X, Y>>)) * m.size();
}

template <typename X, typename Y, typename Z>
static inline size_t IncrementalDynamicUsage(const std::map<X, Y, Z> &m) {
    return MallocUsage(sizeof(stl_tree_node<std::pair<const X, Y>>));
}

// indirectmap has underlying map with pointer as key

template <typename X, typename Y>
static inline size_t DynamicUsage(const indirectmap<X, Y> &m) {
    return MallocUsage(sizeof(stl_tree_node<std::pair<const X *, Y>>)) *
           m.size();
}

template <typename X, typename Y>
static inline size_t IncrementalDynamicUsage(const indirectmap<X, Y> &m) {
    return MallocUsage(sizeof(stl_tree_node<std::pair<const X *, Y>>));
}

template <typename X>
static inline size_t DynamicUsage(const std::unique_ptr<X> &p) {
    return p ? MallocUsage(sizeof(X)) : 0;
}

template <typename X>
static inline size_t DynamicUsage(const std::shared_ptr<X> &p) {
    // A shared_ptr can either use a single continuous memory block for both the
    // counter and the storage (when using std::make_shared), or separate. We
    // can't observe the difference, however, so assume the worst.
    return p ? MallocUsage(sizeof(X)) + MallocUsage(sizeof(stl_shared_counter))
             : 0;
}

template <typename X> struct list_node {
private:
    void *ptr_next;
    void *ptr_prev;
    X x;
};

template <typename X> static inline size_t DynamicUsage(const std::list<X> &l) {
    return MallocUsage(sizeof(list_node<X>)) * l.size();
}

// Boost data structures

template <typename X> struct unordered_node : private X {
private:
    void *ptr;
};

template <typename X, typename Y>
static inline size_t DynamicUsage(const std::unordered_set<X, Y> &s) {
    return MallocUsage(sizeof(unordered_node<X>)) * s.size() +
           MallocUsage(sizeof(void *) * s.bucket_count());
}

template <typename X, typename Y, typename Z>
static inline size_t DynamicUsage(const std::unordered_map<X, Y, Z> &m) {
    return MallocUsage(sizeof(unordered_node<std::pair<const X, Y>>)) *
               m.size() +
           MallocUsage(sizeof(void *) * m.bucket_count());
}

template <class Key, class T, class Hash, class Pred,
          std::size_t MAX_BLOCK_SIZE_BYTES, std::size_t ALIGN_BYTES>
static inline size_t DynamicUsage(
    const std::unordered_map<Key, T, Hash, Pred,
                             PoolAllocator<std::pair<const Key, T>,
                                           MAX_BLOCK_SIZE_BYTES, ALIGN_BYTES>>
        &m) {
    auto *pool_resource = m.get_allocator().resource();

    // The allocated chunks are stored in a std::list. Size per node should
    // therefore be 3 pointers: next, previous, and a pointer to the chunk.
    size_t estimated_list_node_size = MallocUsage(sizeof(void *) * 3);
    size_t usage_resource =
        estimated_list_node_size * pool_resource->NumAllocatedChunks();
    size_t usage_chunks = MallocUsage(pool_resource->ChunkSizeBytes()) *
                          pool_resource->NumAllocatedChunks();
    return usage_resource + usage_chunks +
           MallocUsage(sizeof(void *) * m.bucket_count());
}

} // namespace memusage

#endif // BITCOIN_MEMUSAGE_H
